There is NEVER less debt than you think, or hope. In the US’ case, there is also c. $200tn of unfunded medicare and pension debt. If Trump is thinking that some of the debt has been issued fraudulently and can thus be revoked then he needs to think again. Just the hint of that would crash the bond market.
What there clearly are is a lot of fraudulent payments. Can DOGE put a halt to enough of them to balance the budget so that a rise in the debt ceiling is unnecessary?
